Universal broadband polarizer, devices incorporating same, and method of making same

ABSTRACT

A polarization dependent device suitable for effecting at least one polarization of a broadband portion of electromagnetic radiation incident upon the device includes a substrate, and a plurality of regions of differing refractive indices positioned in an alternating manner and substantially adjacent to the substrate to effect the at least one polarization impinging on the regions. The plurality of regions are oriented with respect to the at least one polarization of the broadband portion of the electromagnetic radiation so as to effect the at least one polarization of the broadband portion of the electromagnetic radiation impinging on the regions.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional application of Ser. No. 10/775,356,filed Feb. 10, 2004 now U.S. Pat. No. 7,268,946, which is acontinuation-in-part application of Ser. No. 10/644,643 filed Aug. 20,2003, now U.S. Pat. No. 7,227,684, which claims priority of provisionalapplication Ser. No. 60/446,200 filed Feb. 10, 2003, the entiredisclosure of which are hereby incorporated by reference.

FIELD OF THE INVENTION

The present invention relates generally to optical components beingsuitable for broadband polarizing and more particularly, for polarizing,combining and beam splitting.

BACKGROUND OF THE INVENTION

Propagating electromagnetic radiation is composed of two orthogonallypolarized components—known as the transverse electric and transversemagnetic fields. In many applications, it is necessary or desired toseparately control the transverse electric (TE) or the transversemagnetic (TM) polarization. Device performance which varies based onpolarization state may be important in optoelectronics, thereby allowingthe possibility of multi-functioning devices. Birefringence is aproperty of a material to divide electromagnetic radiation into thesetwo components, and may be found in materials which have two differentindices of refraction, referred to as n⊥ and n∥ (or n_(p) and n_(s)), indifferent directions, often orthogonal, (i.e., light entering certaintransparent materials, such as calcite, splits into two beams whichtravel at different speeds). Birefringence is also known as doublerefraction. Birefringence may serve to provide the capability ofseparating these two orthogonal polarization, thereby allowing suchdevices to manipulate each polarization independently. For example,polarization may be used to provide add/drop capabilities, beamsplitincoming radiation, filter, etc.

However, a need therefore exists for devices in which polarization oftraversing and incident electromagnetic spectrum may be controlled overa broad spectral range, thereby providing broadband polarizationcontrol.

SUMMARY OF THE INVENTION

A polarization dependent device suitable for effecting at least onepolarization of a broadband portion of electromagnetic radiationincident upon the device is disclosed. This device includes a substrate,and a plurality of regions of differing refractive indices positioned inan alternating manner and substantially adjacent to the substrate toeffect the at least one polarization impinging on the regions. Theplurality of regions are oriented with respect to the at least onepolarization of the broadband portion of the electromagnetic radiationso as to effect the at least one polarization of the broadband portionof the electromagnetic radiation impinging on the regions.

BRIEF DESCRIPTION OF THE FIGURES

Understanding of the present invention will be facilitated byconsideration of the following detailed description of the preferredembodiments of the present invention taken in conjunction with theaccompanying drawings, in which like numerals refer to like parts, and:

FIG. 1 illustrates a cross section of the present device according to anaspect of the present invention;

FIGS. 2A-2C each illustrate the operation of the device of FIG. 1according to aspects of the present invention;

FIG. 3 illustrates a simulation of the resultant reflection andtransmission of the device of FIG. 1 with respect polarization of thebeam;

FIG. 4 illustrates a cross section of a device according to an aspect ofthe present invention;

FIG. 5 illustrates a cross section of a device according to an aspect ofthe present invention;

FIG. 6 illustrates a cross section of a device according to an aspect ofthe present invention;

FIG. 7 illustrates an image of a device according to an aspect of thepresent invention;

FIG. 8 illustrates a device according to an aspect of the presentinvention; and,

FIG. 9 illustrates an image of a device according to an aspect of thepresent invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

It is to be understood that the figures and descriptions of the presentinvention have been simplified to illustrate elements that are relevantfor a clear understanding of the present invention, while eliminating,for the purpose of clarity, many other elements found in typicalphotonic components and methods of manufacturing the same. Those ofordinary skill in the art will recognize that other elements and/orsteps are desirable and/or required in implementing the presentinvention. However, because such elements and steps are well known inthe art, and because they do not facilitate a better understanding ofthe present invention, a discussion of such elements and steps is notprovided herein. The disclosure herein is directed to all suchvariations and modifications to such elements and methods known to thoseskilled in the art.

In general, according to an aspect of the present invention, control ofpolarization may be used to control electromagnetic waves. Use ofpolarization to control electromagnetic waves may reduce negativewavelength dependent effects often associated with wavelength controltechniques, such as transmission roll-offs, non-uniformity oftransmission, and transmission variation with respect to wavelength.Such polarization control may be effected using sub-operating wavelengthoptical structures, such as nanostructures or nanoelements, where theoperating wavelength corresponds to the electromagnetic waves. Suchpolarization control over a broadband of wavelengths, such as visibleand infrared, for example, adds to the usefulness of the control.Further, broadband may be defined to include a subset of the visiblespectrum and a subset of the infrared spectrum, such as wavelengths from300-1000 nm, 500-1100 nm, and 550-1000 nm, by way of non-limitingexample only. Further, broadband may be defined to include multiplecommunication channels, such as 1000-1200 nm, by way of non-limitingexample only. Further, broadband may be defined to include substantialportions of either the visible spectrum or infrared spectrum, or both,as would be conventionally understood by those having an ordinary skillin the pertinent arts.

Referring now to FIG. 1, there is shown a device 10 according to anaspect of the present invention. Device 10 may generally include asubstrate 100 and a pattern of nanostructures 150 positionedsubstantially adjacent to substrate 100. Pattern of nanostructures 150may include a plurality of regions 200 and 210 of differing refractiveindices positioned in an alternating manner. Device 10 may also includea layer 105 positioned substantially adjacent to substrate 100 distal topattern of nanostructures 150.

Substrate 100 may take the form of any material suitable for use inoptics and known by those possessing ordinary skill in the pertinentarts. Suitable materials for substrate 100 may include materialscommonly used in the art of grating or optic manufacturing, such asglass (like BK7, Quartz or Zerodur, for example), semiconductors,Faraday magnetic-optic materials, such as garnets, and materialsincluding elements such as bismuth, iron, gallium, and oxygen, forexample, and polymers including plastics such as polycarbonate, by wayof non-limiting example only. Further, substrate 100 may include acomposite substrate having multiple layers incorporating such materials.Substrate 100 may be any thickness, such as a thickness within the rangeof 1-10,000 μm, for example. More specifically substrate 100 may have athickness of approximately 1000 μm, 500 μm, 200 μm, 100 μm, 50 μm, 20μm, 5 μm, by way of non-limiting example only.

Pattern of nanostructures 150 may include a plurality of regionsoriented with respect to the at least one polarization of the broadbandportion of the electromagnetic radiation so as to effect the at leastone polarization of the broadband portion of the electromagneticradiation impinging on the regions.

Pattern of nanostructures 150, including nanoelements or sub-wavelengthelements, may include multiple elements each of width W and height H.Width W may be from about 10 to 500 nm or from about 15 to 180 nm.Height H may be between about 10 to 1000 nm, or about 30 to 500 nm.Further, the dimensions of the elements may vary, be chirped, or betapered as will be understood by those possessing an ordinary skill inthe pertinent arts.

Pattern of nanostructures 150 may have a period of nanoelements, P. Thisperiod may also be substantially constant or varied or chirped. Period Pmay be between about 10 nm and 1000 nm, or 30 nm and 200 nm. As may beseen in FIG. 1, nanostructures 150 may form areas of alternatingrefractive indices. In FIG. 1, for example, a first index material 200,having a refractive index n_(F), may be positioned substantiallyadjacent to a second index material 210, having a refractive indexn_(O), creating alternating regions of relatively high and low indices,respectively. The filling ratio of pattern of nanostructures 150,denoted W/P, may be defined as the ratio of the width of the index areaof the higher of the two refractive index elements within the period tothe overall period. Filling ratio, W/P, may determine an operatingwavelength of the device as will be understood by to one possessing anordinary skill in the pertinent arts.

First index material 200 may take the form of conductive materials knownto those possessing an ordinary skill in the pertinent arts, such asaluminum, gold, silver, copper, and alloys of these materials, by way ofnon-limiting example only. Second index material 210 may take the formof air, a vacuum, or a dielectric material such as silicon dioxide,metal oxide, metal fluoride, organic polymer containing hydrocarbon,inorganic liquid, organic liquid, or glass, by way of non-limitingexample only. According to an aspect of the present invention firstindex material 200 may have a higher refractive index than second indexmaterial 210. For completeness, there may be multiple materials 210,200, each occupying a portion of overall period P. This portion may befunctionally represented as:

${{f_{k} = \frac{F_{Gk}}{X_{G}}};{{{for}\mspace{14mu} k} = 1}},2,3,\ldots\mspace{14mu},{M;{{{and}\mspace{14mu}{\sum\limits_{k = 1}^{M}\; f_{k}}} = 1}}$

where the characteristic dimension P is less than the operatingwavelength of the device, such as, for example, an operating wavelengthλ=1550 nm and P on the order of 10 to 1000 nm, and more specificallyfrom 30 to 200 nm.

Pattern of nanostructures 150 may be grown or deposited on substrate100. Pattern of nanostructures 150 may be formed into or onto substrate100 using any suitable nanolithography and/or nano-replicating process,such as Sub-Micron-Scale patterning as described in U.S. Ser. No.60/496,193. Other processes for producing pattern of nanostructures 150include interference lithography such as holographic lithography, stepand flash imprint lithography, nanoimprint lithography, softlithography, deep UV (DUV) photolithography, extreme UV (EUV)lithography, X-ray lithography, E-beam lithography, ion-beam lithographyand laser assisted direct imprint, by way of non-limiting example only.

According to an aspect of the present invention, an underlyingone-dimensional (1-D) pattern of nanostructures 150, of materials ofhigh contrast refractive index, forming high and low refractive indexareas with distinct differences in refractive index, may be so formed onsubstrate 100. According to an aspect of the present invention,two-dimensional (2-D) pattern of nanostructures 150, formed of materialsof high contrast refractive index may be so formed on substrate 100.

As will be recognized by those possessing ordinary skill in thepertinent arts, various elements in pattern 150 may be replicated insuch a manner onto or into substrate 100. Such elements may take theform of strips, trenches, pillars, or holes, for example, all of whichmay have a common period or not, and may be of various heights andwidths. Strips may take the form of rectangular grooves, for example, oralternatively triangular or semicircular grooves, by way of non-limitingexample. Similarly pillars, basically the inverse of holes, may bepatterned. Such pillars may be patterned with a common period in eitheraxis or alternatively by varying the period in one or both axes. Thepillars may be shaped in the form of, for example, elevated steps,rounded semi-circles, or triangles. The pillars may also be shaped withone conic in one axis and another conic in another, for example.

Layer 105 may be included within device 10 to provide or enhance opticaloperability of device 10. This layer, if present, may take the form ofan anti-reflection coating, for example. For the sake of completeness,layer 105 may include multiple layers, such as a plurality of layers,which collectively, perform an anti-reflection function. In such aconfiguration, layer 105 may include alternating layers of SiO₂ andHFO₂, each layer having a thickness ranging from 20 nm to 200 nm. Atotal of four layers may be used. Other numbers of layers may also beused, as would be evident to those possessing an ordinary skill in thepertinent arts.

As is known to those possessing an ordinary skill in the pertinent arts,an anti-reflection coating (ARC) may take the form of a thin, dielectricor metallic film, or several such films, applied to an optical surfaceto reduce its reflectance and thereby increase the overalltransmittance. A single quarter-wavelength coating of optimum index mayeliminate reflection at one wavelength. Multi-layer coatings may reducethe loss over the visible spectrum. The idea behind anti-reflectioncoatings is that the creation of a double interface by means of a thinfilm gives you two reflected waves. If these waves are out of phase,they partially or totally cancel. If the coating is a quarter wavelengththickness and the coating has an index of refraction less that the glassit is coating then the two reflections are 180 degrees out of phase. Ifthe first surface reflection resulting from radiation incident on thefirst surface of an ARC is 4% of the overall radiation impinging ondevice 10 and the second reflection resulting from radiation incident onthe second surface of an ARC is 4% of the radiation transmitted by thecoating layer (or 96% of the impinging radiation in this example) and180 degrees out of phase near cancellation will result as will beapparent to those possessing an ordinary skill in the pertinent arts. Inthis example, the first reflection is 4% of the impinging radiation andthe second reflection is 4% of 96% of the impinging radiation with eachreflection out of phase by 180 degrees. If numerically these were equalno reflection would exist as each reflection would be totally canceled.In reality, a small reflection may still exist as 4% and 3.84% (96% of4%) are not exactly equal. Nonetheless, the ARC has worked to reduce thereflection from 4% to 0.16% in this example.

Such a device, configured as described hereinabove, may provide anextinction ratio greater than approximately 100 in transmission over awavelength range of 390 nm to 1600 nm, for example, and may have atransmittance greater than 0.50 over a wavelength range of 390 nm to1600 nm, for example.

Referring now to FIGS. 2A-2C, there are shown a set of schematicdiagrams illustrating operation of device 10 of FIG. 1 according to anaspect of the present invention. In FIG. 2A, there is shown theoperation of a polarizing beam splitter according to an aspect of thepresent invention. As may be seen in FIG. 2A, radiation containing bothTE and TM components may be incident upon device 10. One of the twocomponents may be transmitted through device 10, shown in FIG. 2A as TMfor example. The other component may be reflected by device 10, shown inFIG. 2A as TE for example. As is known to those possessing an ordinaryskill in the pertinent arts, a polarizing beam splitter utilizingparallel conductors, such as nanostructure 150, may serve to transmitpolarized radiation perpendicular to the length of the conductors andanalogously, reflect radiation parallel to the length of the conductors.

Such a polarizer may be used for beam splitting, combining,polarization, or like-functions, and may be formed of a series ofnanostructures. Wherein radiation, such as visible or infrared light,strikes the nanostructure, some of that radiation is reflected, whilethat portion of the radiation that is selectively polarized by thenanostructure may pass. Such a nanostructure polarizer polarizes theradiation wave incident on the parallel conductors perpendicularly tothe length of the conductors.

The nanostructure may be dense and may be closer together than thewavelength of the radiation to be polarized, controlled, or analyzed.Thus, the smaller the wavelength of the radiation, the more dense thenanostructure may be in order to operate on the subject radiation. Thishas been, as is known in the art, a limitation on the types of radiationthat may be polarized using such a polarizer. The polarization ofradiation may be used to control the radiation that is the subject ofthe polarization, such as in a splitter or combiner, and to analyze thepolarization characteristics of an object, such as by examining thelight reflected from, or by, an object. Polarization characteristics mayprovide for extraction of significant information about the physical andchemical makeup of an object and of a surface. A polarizing beamsplitter may thus act as an analyzer, for example, reflecting unwantedlight, and passing desired light. Exemplary optical and electro-opticalpolarizer applications may include lasers, glare-reduction, lenscoating, display enhancement, and exploitation of limited bandwidthavailability, to name a few. For example, through “frequency reuse,” anantenna may simultaneously transmit adjacent beams at a same frequency,and, by polarizing each beam differently, nonetheless maintain usefulbeam isolation. In the fields of optics, telecommunications, optical andelectro-optical applications and photonics, it may be highly desirableto enhance device performance and reduce fabrication, packaging andassembly costs, such as by providing polarization capabilities thatprovide improved performance through a broader range of radiation, butthat may be fabricated at low cost. For example, it may be desirable toprovide a improved photonic component, which may be incorporated into aPhotonic Integrated Circuit (PIC), or with another photonic device.

In FIG. 2B, there is shown the operation of a polarizing beam combineraccording to an aspect of the present invention. As may be seen in FIG.2B, radiation primarily oriented with one component (shown as TE in FIG.2B) may be incident on one side of device 10. The other component ofradiation (shown as TM in FIG. 2B) may be incident on a differentsurface of device 10. Device 10, configured according to an aspect ofthe present invention, may reflect the TE component while transmittingthe TM component. Since these components were incident on opposite sidesof device 10, the different reaction characteristics of device 10 serveto combine these two components in one beam, as is shown in FIG. 2B. Apolarizing beam combiner utilizing parallel conductors, such asnanostructure 150, transmits polarized radiation perpendicular to thelength of the conductors and similarly, reflects radiation parallel tothe length of the conductors.

In FIG. 2C, there is shown the operation of a polarizer according to anaspect of the present invention. As may be seen in FIG. 2C, radiationcontaining both TE and TM components may be incident upon device 10. Oneof the components is transmitted by device 10 (shown as TM in FIG. 2C),while the other (shown as TE in FIG. 2C) is absorbed in device 10. As isknown to those possessing an ordinary skill in the pertinent arts, apolarizer utilizing parallel conductors, such as nanostructure 150,transmits polarized radiation perpendicular to the length of theconductors.

Referring now to FIG. 3, there is shown a simulation of the resultantreflection and transmission of device 10 of FIG. 1 with respect to thepolarization of the beam. Specifically, the parameters of device 10include aluminum nano-gratings with a period (P) of 100 mm, a height (H)of 150 nm, and a width (W) of 50 nm. In this simulation is incident ondevice 10 at approximately 45 degrees. As may be seen in FIG. 3, thecomponent transmission TM is achieved above 83% for wavelengths between350 and 1600 nm. The component reflected TE is greater than 98% forwavelengths between 300 and 1600 nm. Further, for transmitted beam, anextinction ratio is better than 40 dB for such a broadband window.

Referring now to FIG. 4, there is shown a cross section of a deviceaccording to an aspect of the present invention. As may be seen in FIG.4, a device 400 is shown. Device 400 may include many of the elementsfound in device 10, such as a substrate 100, a layer 105, a plurality ofnanoelements 150 including a first index material 200, having arefractive index n_(F), positioned substantially adjacent to a secondindex material 210, having a refractive index n_(O), creating analternating regions of relatively high and low indices, respectfully.Device 400 additionally may have dielectric layer 410. Dielectric layer410 may be a dielectric material forming a thin film layer on at leastone surface of device 400. This dielectric layer may take the form ofsilicon dioxide, for example. Dielectric layer 410 may be positionedsubstantially about the device or substantially along one edge, as shownin FIG. 4. This wrapping of dielectric layer 410 may improve thereliability of the device 410. Dielectric layer 410 may have a thicknessin the range of 1 nm to 50 nm and may include silicon dioxide, organicpolymer, silicon nitride, silicon oxynitride, magnesium fluoride andmetal oxide.

Referring now to FIG. 5, there is shown a cross section of a device 500according to an aspect of the present invention. Device 500 may includea substrate 100, anti-reflection coatings 105, 110, and 140, thin films120 and 130 and nanograting 150. As is shown in FIG. 5, each of theselayers may be aligned substantially adjacent to the preceding layer insandwiched configuration similar to that described hereinabove.Substrate 100 may have anti-reflection coating 105 placed substantiallyadjacent thereto. Distal to anti-reflection coating 105 on substrate 100may be placed anti-reflection coating 110. Substantially adjacent tocoating 110 and distal to substrate 100 may be placed a thin film 120.Substantially adjacent to thin film 120 may be nanograting 150 alignedsubstantially adjacent not distal to thin film 120.

Substrate 100, as discussed hereinabove with respect to FIG. 1, may takethe form of any material suitable for use in optics and known by thosepossessing ordinary skill in the pertinent arts.

Pattern of nanostructures 150, as discussed hereinabove with respect toFIG. 1, including nanoelements or sub-wavelength elements, may includemultiple elements each of width W and height H. The dimensions of theelements may vary or be chirped as will be understood by thosepossessing an ordinary skill in the pertinent arts. Pattern ofnanostructures 150 may have a period of nanoelements, P. This period mayalso be varied or chirped. As will be recognized by those possessingordinary skill in the pertinent arts, various patterns may be replicatedin such a manner onto or into substrate 100.

Anti-reflection coatings 105, 110 and 140 may be included within device500. For the sake of completeness, coatings 105, 110 and 140 may includemultiple layers designed to perform the anti-reflection function. Whilemultiple layers may be, and commonly are, used the present discussionrefers to layer 105 for a single or multiple layer performing theidentified function.

As is known to those possessing an ordinary skill in the pertinent arts,an anti-reflection coating (ARC), such as anti-reflection coating 105,110, and 140 may take the form of a thin, dielectric or metallic film,or several such films, applied to an optical surface to reduce itsreflectance and thereby increase the overall transmittance.

Thin films 120, 130 may be utilized to provide an etch stop duringprocessing, for example. If utilized as an etch stop, films 120 and 130may be designed to incorporate the properties known to those possessingan ordinary skill in the pertinent arts with respect to semiconductorfabrication. In particular, thin films 120 and 130 may be designed witha material having a different etch rate than the material to be etchedand may be placed underneath the etched layer to provide a buffer duringetching.

Referring now to FIG. 6, there is shown a device 600 suitable for use asa universal broadband polarizing beamsplitter, polarizing beam combiner,and polarizer. Device 600 contains many of the elements shown anddiscussed with respect to device 500 of FIG. 5 above. Device 600 mayfurther include a filler material 300 incorporated into the regionbetween first index material 200. Material 300 may take the form of alow index material, for example. By way of non-limiting example only,material 300 may be used to provide mechanical stability to device 600,optical interfacing for device 600, such as by index matching, forexample. Material 300 may take the form of a dielectric material, suchas silicon dioxide, a polymer material or other materials known by thosepossessing an ordinary skill in the pertinent arts to substantiallyperform dielectric functions. Filler material 300 may include conductivematerial, as discussed hereinabove.

By way of specific non-limiting example, device 600 may include asubstrate 100, such as glass, coated with a multiple, such as two,layers 110, which may form of an anti-reflection coating, such as alayer of HFO₂ and a layer of SiO₂ each having a thickness in the rangeof 20 nm to 300 nm. Additionally, an etch stop layer 120, such as Al₂O₃,having a thickness in the range of 10 nm to 50 nm may be placedsubstantially adjacent to layer 110. A nanograting 150 may be includedsubstantially adjacent to layer 120 and distal to layer 110.Substantially surrounding nanograting 150 may be a protective layer 130,such as Al₂O₃, with a thickness in the range of 1 nm to 20 nm. A filler210, such as SiO₂, may also be used in the alternating regions ofnanograting 150, placed in an alternating manner with elements 200. Anintermediate dielectric layer (not shown), such as SiO₂, may also beused. Such a layer may be applied with a thickness of 20 nm to 200 nm.This intermediate dielectric layer may protect adjacent layers duringthe fabrication process, or provide index matching, or other propertiesas would be known to those possessing an ordinary skill in the pertinentarts. Such an intermediate dielectric layer may be placed substantiallybetween and adjacent to substrate 100 and nanograting 150. Othersuitable location may similarly, as would be apparent to thosepossessing an ordinary skill in the pertinent arts, be used for thisintermediate layer. A suitable anti-reflection coating 140 may also beadded substantially adjacent to layer 130, as described hereinabove.Similarly, an anti-reflection coating 105 may be placed adjacent tosubstrate 100 distal to coating 110.

Referring now to FIG. 7, there is shown an image 700 of a deviceaccording to an aspect of the present invention. As may be seen in FIG.7, image 700 illustrates a substrate 100 comprising glass, a pluralityof regions 150 including alternating first 200 and second 210 indexmaterials, the plurality of regions 150 being positioned substantiallyadjacent to substrate 100, and a thin dielectric layer 410 positionedsubstantially adjacent to the plurality of regions 150 and distal tosubstrate 100. As may been seen in FIG. 7, image 700 was taken with amagnification of 91,650 (91K) and shows plurality of regions 150 havinga period of approximately 150 nm.

While plurality of regions 150 described hereinabove illustrates twoalternating materials forming a pattern, wherein a first material isdesignated as “A” and a second material is designated as “B”, such asABABAB . . . , other patterns may also be formed. The present inventionmay include other materials within the pattern making up plurality ofregions 150. For example three alternating materials may be usedcreating a pattern such as ABCABCABC . . . . Further, four materials maybe used producing a pattern ABCDABCDABCD . . . . Other numbers ofmaterials may also be used producing patterns as described herein.

Referring now to FIG. 8, there is shown a device 800 according to anaspect of the present invention. As may be seen in FIG. 8, device 800may include a substrate 100, an etch stop layer 120, plurality ofregions 150 may include a plurality of filling material 810, a pluralityof high index material 200, and a plurality of low index material 210,and anti-reflection coatings 105 and 110.

Similar to the devices discussed hereinabove, substrate 100 may includeglass, semiconductor materials, Faraday magneto-optic materials, by wayof non-limiting example only. Anti-reflection coatings 105 and 110 maybe formed of alternating layers of HFO₂ and SiO₂. Similarly, etch stoplayer 120 may be formed of HFO₂ and may also include materials to formanti-reflection coatings.

Plurality of regions 150 may include a plurality of filling material810, a plurality of high index material 200, and a plurality of lowindex material 210 arranged in an alternating manner, such as fillingmaterial 810, plurality of low index material 210, and plurality of highindex material 200, for example. According to an aspect of the presentinvention, filling material 810 may have a low or high index. Fillingmaterial having a low index may include SiO₂, as well as voids of airand vacuum. High index material 200 may include, as describedhereinabove, metals, metal alloys, and combinations of metals. Metalssuited for use as the high index material may include aluminum, gold,chromium, by way of non-limiting example only. Low index material 210may include SiO₂, silicon nitride, and silicon, by way of non-limitingexample only.

Referring now to FIG. 9, there is shown an image 900 of a deviceaccording to an aspect of the present invention. As may be seen in FIG.9, image 900 shows a substrate 100 comprising glass, a plurality ofregions 150 including alternating high 200 and low 210 index materials,plurality of filler 810, an etch stop layer 120, and anti-reflectioncoatings 105 and 110. Plurality of regions 150 may be positionedsubstantially adjacent to substrate 100 as shown. As may been seen inFIG. 9, image 900 was taken with a magnification of 72,000 and showsplurality of regions 150 having a period of approximately 200 nm.

Those of ordinary skill in the art will recognize that manymodifications and variations of the present invention may be implementedwithout departing from the spirit or scope of the invention. Thus, it isintended that the present invention covers the modifications andvariations of this invention provided they come within the scope of theappended claims and their equivalents.

1. A polarization dependent device, said device comprising: a substrate;a plurality of regions of differing refractive indices positioned in analternating manner and substantially adjacent to said substrate, saidplurality of regions comprising a plurality of spaced-apart strips of afirst material extending along a common direction, each strip comprisinga top surface distal from said substrate and a pair of sidewallsextending between the substrate and the top surface; and, a continuousdielectric layer conformally covering the top surface and sidewalls ofthe spaced-apart strips, where the dielectric layer has a uniformthickness in a range from 1 nm to 50 nm, wherein the polarizationdependent device is a polarizer for incident light at at least onewavelength in a range from 300 nm to 1600 nm.
 2. The device of claim 1,wherein said device effects the at least one polarization of broadbandelectromagnetic radiation incident upon the device by at least one ofbeamsplitting, beam combining, absorbing and reflecting the radiation atthe at least one wavelength.
 3. The device of claim 1, wherein saiddevice has an extinction ratio greater than approximately 100 intransmission over a wavelength range of 390 nm to 1650 nm.
 4. The deviceof claim 1, wherein said device has a transmittance greater than 0.50over a wavelength range of 390 nm to 1650 nm.
 5. The device of claim 1,further comprising at least one anti-reflection coating.
 6. The deviceof claim 5, wherein said at least one anti-reflection coating enhancestransmission at the at least one wavelength by reducing unwantedreflections.
 7. The device of claim 1, wherein the conformal dielectriclayer is a metal oxide.
 8. The device of claim 1, wherein the conformaldielectric layer is silicon dioxide, silicon nitride, siliconoxynitride, or magnesium fluoride.
 9. The device of claim 1, wherein theconformal dielectric layer is an organic polymer.
 10. The device ofclaim 1, wherein the strips have a width in a range from about 10 nm to500 nm.
 11. The device of claim 1, wherein the strips have a width in arange from about 15 nm to 180 nm.
 12. The device of claim 1, wherein thestrips have a height in a range from about 10 nm to 1,000 nm.
 13. Thedevice of claim 1, wherein the strips have a height in a range fromabout 30 nm to 500 nm.
 14. The device of claim 1, where the strips arearranged as a grating having a period in a range between about 10 nm and1,000 nm.
 15. The device of claim 1, where the strips are arranged as agrating having a period in a range between about 30 nm and 200 nm. 16.The device of claim 1, where the strips are arranged as a grating havinga period that is constant or varied or chirped.
 17. A polarizationdependent device suitable for effecting at least one polarization ofbroadband electromagnetic radiation incident upon the device, saiddevice comprising: a substrate; a plurality of regions of differingrefractive indices positioned in an alternating manner and substantiallyadjacent to said substrate to effect the at least one polarizationimpinging on said regions, said plurality of regions comprising aplurality of spaced-apart strips of a first material extending along acommon direction, each strip comprising a top surface distal from saidsubstrate and a pair of sidewalls extending between the substrate andthe top surface; at least one anti-reflection coating; and a continuousdielectric layer conformally covering the top surface and sidewalls ofthe spaced-apart strips, where the dielectric layer has a uniformthickness in a range from 1 nm to 50 nm regions; and, wherein saiddevice has an extinction ratio greater than approximately 5000 intransmission over a wavelength range of 1250 nm to 1350 nm, and whereinsaid device has a transmittance greater than 0.96 over a wavelengthrange of 1250 nm to 1350 nm.
 18. A polarization dependent devicesuitable for effecting at least one polarization of broadbandelectromagnetic radiation incident upon the device, said devicecomprising: a substrate; a plurality of regions of differing refractiveindices positioned in an alternating manner and substantially adjacentto said substrate to effect the at least one polarization impinging onsaid regions, said plurality of regions comprising a plurality ofspaced-apart strips of a first material extending along a commondirection, each strip comprising a top surface distal from saidsubstrate and a pair of sidewalls extending between the substrate andthe top surface; at least one anti-reflection coating; and a continuousdielectric layer conformally covering the top surface and sidewalls ofthe spaced-apart strips, where the dielectric layer has a uniformthickness in a range from 1 nm to 50 nm, wherein said device has anextinction ratio greater than approximately 5000 in transmission over awavelength range of 1450 nm to 1650 nm, and wherein said device has atransmittance greater than 0.96 over a wavelength range of 1450 nm to1650 nm.